To show that shipping bytecode files without source, as a form of obfuscation,
is not the best option available

Provide a minification of Python source code when total byte size of source
code is paramount

When people ship Python code as only bytecode files (i.e. only .pyo files
and no .py files), there are couple drawbacks. First and foremost, it
prevents users from using your code with all available Python interpreters such
as Jython and IronPython. Another drawback is that it is a poor form of
obfuscation as projects like Meta allow you to take bytecode and
reverse-engineer the original source code as enough details are kept that the
only details missing are single-line comments.

When the total number of bytes used to ship Python code is paramount, then
you want to minify the source code. Bytecode files actually contain so much
detail that the space savings can be miniscule (e.g. the decimal module from
Python’s standard libary, which is the largest single file in the stdlib, has a
bytecode file that is only 5% smaller than its original source code).

The version number for mnfy is PEP 386 compliant, taking the form of
PPP.FFF.BBB. The FFF.BBB represents the feature and bugfix version
numbers of mnfy itself. The PPP portion of the version number represents the
Python version that mnfy is compatible with:
'{}{}'.format(*sys.version_info[:2]).

The Python version that mnfy is compatible with is directly embedded in the version
number as Python’s AST is not guaranteed to be backwards-compatible. This means
that you should use each version of mnfy with a specific version of Python.
Since mnfy works with source code and not bytecode you can safely use
mnfy on code that must be backwards-compatible with older versions of Python,
just make sure the interpreter you use with mnfy is correct and can parse the
source code (e.g. just because
the latest version of mnfy only works with Python 3.3 does not mean you cannot
use that release against source code that must work with Python 3.2, just make
sure to use a Python 3.3 interpreter with mnfy and that the source code can be
read by a Python 3.3 interpreter).

TL;DR: pass the file you want to minify as an argument to mnfy and it will
print to stdout the source code minified such that the AST is exactly the
same as the original source code. To get transformations that will change the
AST to varying degrees you will need to specificy various flags.